Search results for "gall"
showing 10 items of 903 documents
Polish Yellow Sweet Clover (Melilotus officinalis L.) Honey, Chromatographic Fingerprints, and Chemical Markers
2017
A case study of Polish Melilotus officinalis honey was presented for the first time. Gas chromatography–mass spectrometry (GC-MS) (after steam distillation, Soxhlet extraction, ultrasonic solvent extraction, and solid phase extraction (SPE)) and targeted high performance liquid chromatography with a photodiode array detector (HPLC-PAD) were applied to determine the characteristic components of honey. While ubiquitous in most honeys, carbohydrates, terpene derivatives, and phenylacetic acid dominated in the Soxhlet extracts (25.54%) and in the application of SPE (13.04%). In addition, lumichrome (1.85%) was found, and may be considered as a marker of this honey. Due to the presence of these …
Chromatographic fingerprint, antioxidant activity, and colour characteristic of polish goldenrod (Solidago virgaurea L.) honey and flower
2018
In recent times, the nutraceutical and pharmaceutical interest in honey due to its well-known health properties has increased. Consumers need clear and precise information, so that they can make informed choices about their diet and the foods they buy. Therefore, gas chromatography–mass spectrometry (GC–MS) and high-performance liquid chromatography with a photodiode array detector (HPLC-PAD) was revealed a general characteristic fingerprint of polish monofloral goldenrod honey and flowers. In addition, high-performance thin-layer chromatography (HPTLC) has proven to be a useful tool for determining similarity patterns of common bands among honey from the same floral source and thus can be …
Chemical analysis and antioxidant activity of the essential oils of three Piperaceae species growing in the central region of Cuba.
2013
The present study describes the phytochemical profile and antioxidant activity of the essential oils of three Piperaceae species collected in the central region of Cuba. The essential oils of Piper aduncum, P. auritum and P. umbellatum leaves, obtained by hydrodistillation, were analyzed by gas chromatography-mass spectrometry. The main components of P. aduncum oil were piperitone (34%), camphor (17.1%), camphene (10.9%), 1,8-cineol (8.7%) and viridiflorol (7.4%), whereas that of P. auritum and P. umbellatum was safrole (71.8 and 26.4%, respectively). The antioxidant properties of the essential oils were also evaluated using several assays for radical scavenging ability (DPPH test and redu…
Size dependent carrier thermal escape and transfer in bimodally distributed self assembled InAs/GaAs quantum dots
2012
We have investigated the temperature dependent recombination dynamics in two bimodally distributed InAs self assembled quantum dots samples. A rate equations model has been implemented to investigate the thermally activated carrier escape mechanism which changes from exciton-like to uncorrelated electron and hole pairs as the quantum dot size varies. For the smaller dots, we find a hot exciton thermal escape process. We evaluated the thermal transfer process between quantum dots by the quantum dot density and carrier escape properties of both samples. © 2012 American Institute of Physics.
‘Dentro la Selva Ercinia’
2008
La digressione sulla Selva Ercinia (De bello Gallico VI, 26-29) è presa in esame da un punto di vista romano, piuttosto che germanico (anche perché Cesare aveva una limitata conoscenza della cultura germanica) e per quanto il suo contenuto può dire degli intendimenti di Cesare. I tre animali descritti (renna, alce, e uro) sono rappresentati secondo le regole del canone letterario e sono stati prescelti per la loro natura topica (e retorica) come emblemi della fauna settentrionale. Cesare vuole anche presentare al suo pubblico nuove specie di animali selvaggi come quelli apprezzati nei ludi circensi e che si potrebbero fare sfilare in un suo trionfo, insistendo al contempo sulla difficoltà/i…
Dendroarchaeological contributions to the history of forest exploitation: the case of the Gallo-roman settlement of Oedenburg (Alsace, France) betwee…
2011
International audience; Dendro-archaeological contribution to the history of forest exploitation. The case of the Gallo-Roman settlement of Oedenburg (Alsace, France) between 10 and 180 AD summary Dendrochronology has never been considered as simply a dating tool. In addition to the dates, which are always based on a regional scale signal, tree-ring series can provide information about forest structure and woodland development. Our study of the settlement of Oedenburg, established in the Rhine Limes of the Roman Empire, was conducted within this framework. The dated series provide a description of some structural aspects of oak-stands that were exploited for construction. In this aim, the a…
Flow spectrophotometric determination of ammonium ion
1999
Abstract A flow procedure is proposed for the determination of ammonium ion. The sample in basic medium is forced through a solid-phase reactor containing immobilized AgCl on polymeric pearl beads. The released Ag + , complexed with the ammonia, gives a blue ternary complex with the aid of bromopyrogallol red and 1,10-phenanthroline which is spectrophotometrically monitored at 636 nm. The calibration graph is linear over the range 1–20 μg ml −1 ammonium ion, detection limit ( s / n = 3) 0.35 μg ml −1 and relative standard deviation (slope) 1.9 % ( n = 7). The sample throughput is 48 h −1 . The influence of foreign compounds is studied and the procedure is applied to ammonium ion determi…
Contribution to the adsorption voltammetric determination of manganese
1994
The adsorption voltammetric determination of Mn(II) with Bromopyrogallol Red (BPR) and Mordant Red 19 (MDR) has been investigated using a hanging drop mercury electrode. In NH3/NH4Cl solution, ligands and Mn(II) complexes give well separated voltammetric peaks after enrichment onto the electrode. The conditions for determining manganese by adsorption voltammetry with these reagents have been investigated in detail, as has the influence of foreign ions on the determination. The detection limits are 4·10−10 mol/L Mn for BPR and 8·10−10 mol/L Mn for MDR, respectively.
Determination of synthetic antioxidants in dairy products and dietetic supplements by micellar liquid chromatography with direct sample injection
2000
A simple and rapid HPLC method for the determination of synthetic antioxidants (propyl gallate, tert-butylhydroquinone, 2,4,5-trihydroxybutyrophenone, nordihydroguaiaretic acid, octyl gallate, 3-tert-butyl-4-hydroxyanisole and dodecyl gallate) in powdered and liquid milk, cream of milk and dietetic supplements is described. The samples are diluted or solved in a micellar solution, filtered and directly injected. The retention behavior of the antioxidants on a C18 column, with micellar mobile phases containing SDS (0.05–0.15 M), n-propanol (1–9%, v/v) and 10 mM phosphate at pH 3, has been studied by using mathematical models. Retention is predicted with errors below 3%. To optimize the mobil…
Direct injection of edible oils as microemulsions in a micellar mobile phase applied to the liquid chromatographic determination of synthetic antioxi…
1999
Abstract A simple and quick procedure for analysis of hydrophobic samples by direct injection in a liquid chromatograph, without previous extraction, has been developed. The sample is solved in a water/sodium dodecyl sulphate/n-pentanol microemulsion without destroying the microemulsion structure, and injected. A micellar mobile phase containing 0.1 M SDS, 2.5% n-propanol and 10 mM phosphate of pH 3 is used. The procedure is applied to the determination of synthetic antioxidants (propyl gallate, tert-butylhydroquinone, 2,4,5-trihydroxybutyrophenone, nordihydroguaiaretic acid, octyl gallate, 3-tert-butyl-4-hydroxyanisole and dodecyl gallate) in sunflower, corn and olive oils. Linear calibrat…